Apparatus for converting textile threads

ABSTRACT

A conversion apparatus for textile thread in which the thread moves in hot gas subject to the action of shock waves which deform and fix the thread.

United States Patent [451 Oct. 24, 1972 Lefebvre [541 APPARATUS FOR CONVERTING TEXTILE THREADS [72] Inventor: Michel S. M. Lefebvre, 41 Rue de Picardie, Saint-Quentin, France [22] Filed: June 18, 1970 21 Appl. No.: 47,383

Related US. Application Data [62] Division of Ser. No. 697,812, Jan. 15, 1968,

Pat. No. 3,534,453.

[30] Foreign Application Priority Data March 24, 1967 France ..6718862 [52] US. Cl. ..57/34 B [51] Int. Cl. ..D02g 1/16 [58] Field of Search ..57/34 R, 34 B, 77.3, 157 R,

Primary Examiner-Wemer H. Schroeder AttorneyAifred W. Vibber ABSTRACT A conversion apparatus for textile thread in which the thread moves in hot gas subject to the action of shock waves which deform and fix the thread.

5 Claims, 18 Drawing Figures pmgm num 24 m2 SHEET 1 0F 4 INVENTOR. Ml'chel s. M. LEFEBVRE wvdwbe AT'I'ORNE Y PATENTEDUETZMBYIZ 3.699.759

SHEET 2 [1F 4 INVENTOR. Michel S. M. LEFEBVRE Al/ Mfl ATTORNEY Pmmiunm 9.999.759

SHEET 4 BF 4 v Mi che\ 5. M. LEFEBVRE APPARATUS FOR CONVERTING TEXTILE THREADS This application is a division of application Ser. No. 697,812, filed Jan. 15, 1968 now US. Pat. No. 3,534,453.

In a known process for converting and more particularly texturizing threads of textile materials, a hot gas stream, for example air, and a thread are introduced into a nozzle. The air stream is rotated and therefore provides a simple, rapid and cheap way of twisting the threads, as well as fixing them in the twisted state. This process is relatively slow and cannot provide very fine texturing.

It is an object of the invention to enable a wide variety of textured yarns, which may or may not have twist, to be produced at speeds, e.g. of the order of 1,500 meters/minutes, never previously approached.

The invention accordingly provides an apparatus for converting textile filaments wherein a filament of fibers or of continuous textile material moves in a preferably hot gas flow; and shockwaves are produced very near the filament and deform the same and by means of heat, fix the fibers in their deformed state.

For a better understanding of the invention, a detailed description will now be given of variants of the process hereinbefore defined and of embodiments of the facilities for carrying such variants into effect, reference being made to the accompanying drawings wherein:

FIG. 1 is a diagrammatic view of an embodiment of a system using the process according to the invention;

FIG. 2 is a diagrammatic view in section of an embodiment of the nozzle of the system shown in FIG. 1;

FIG. 2a is a view in end elevation of an axial section on the line Il-II of the nozzle shown in FIG. 2;

FIG. 3 is a diagrammatic sectioned view of another embodiment of the facility according to the invention;

FIG. 4 is a diagrammatic sectioned view of another embodiment of the nozzle;

FIG. 4a is an end view corresponding to FIG. 4;

FIG. 5 is a diagrammatic sectioned view of a dye evaporator associated with a nozzle;

FIG. 6 is a diagrammatic sectioned view of another embodiment;

FIG. 7 is a diagrammatic end view of a variant of the facility shown in FIG. 6;

FIG. 8 shows how the facility shown in FIG. 6 can be used to copy a yarn which has already been texturized;

FIG. 9 is a sectioned plan view of a nozzle operating in accordance with another variant of the process according to the invention;

FIG. 10 is a view in axial section of the nozzle shown in FIG. 9;

FIG. 11 shows a variant of the facility shown in FIG.

FIG. 12 is a view in axial section of the facility shown in FIG. 11;

FIGS. 13 and 14 show another variant of the facilities shown in FIGS. 9 and 11; and

FIGS. 15 and 16 show another variant of the facilities show'riin FIGS. 9 and 11.

In the process according to the invention, a thread 1 (FIGS. 1 and 2), is brought into a nozzle 2 comprising an inlet annulus 3, an elongated duct 4 and intake duct 5. The thread 1 enters the interior of the nozzle 2 through a central orifice 6, and a stream of hot gas such as air at a pressure above the critical pressure enters the bulb or annulus 3 through the duct 5. The radial and axial inclination of the duct 5 relatively to the nozzle axis is such as to produce the familiar effect of the required amount of twisting, fixing and untwisting. The air then flows first through a convergent portion 7 and then through a divergent portion 8 and the flow becomes supersonic. Near the thread 1 the flow changes over abruptly from supersonic to subsonic, so that a shock wave is produced which deforms the thread at the height of the bulb 3. As the thread moves along inside the nozzle 2, the shock waves thus produced texturize, in accordance with the invention, the threadover its whole length so that a texturized roving or yarn 9 is obtained at the nozzle exit. Consequently, the thread 1 in the nozzle 2 is given texturizing effects produced from the shock waves and twisting effects produced by the whirling flows.

The fibers at the level of the bulb 3 have a very high temperature. There is, therefore, heat fixing of the deformation by direct contact between the thread and the hot fluid, so that the heat is absorbed very rapidly.

FIG. 1 shows a complete installation in which the nozzle 2 is associated with a reactor 10 disposed inside an electric oven 1 1. The reactor 10 takes the form of a large-diameter tube which heats the air and increases its kinetic energy. Thread 1 from a bobbin 12 is moved by a doffing cylinder 13 which evens out uneven tensioning, whereafter the thread 1 goes through a grid or ring-type tensioner 14 which determines the tension between the first offer 13 and a second doffer 15, the textured yarn being taken up on a bobbin 16. One possibility with this system is that the tension of the yarn in the nozzle can be varied so that textured products of different qualities can be obtained.

In another variant, shown in FIG. 3, the process according to the invention provides for the association of two identical nozzles 17,18 connected to a common hot-air supply duct 19. The path of the yarn or thread 1 is the common axis for the two nozzles. The yarn l is rotated to the right in one nozzle and then to the left in the other so that a local twist which the hot fluid fixes by heat is produced at a place 20.

In another variant of the process according to the invention, and shown in FIGS. 4 and 4a, a separate hotfluid supply duct 5 centered on the axis of the nozzle 2 can be used for each nozzle, in which event the associated twist feature disappears and the texturizing effect is the result solely of the shock waves.

In another variant of the invention, shown in FIG. 5, each nozzle of the kind just described can be associated with a dye evaporator mainly comprising a tank 21 and two ducts 22,23 connected to the hot air supply duct 5. Liquid 24 to be evaporated goes through the duct 23 into the duct 5 and is evaporated therein. One feature of this process is that, in cases in which the evaporator is associated with noules in which the fluid forms a whirling motion, dyed textured yarns can be produced which have a high dye concentration also, the dye can be injected while the fiber yarn is at its most spreadout, thus ensuring satisfactory dyeing throughout the body of the yarn. Also, two different dyes can be injected into the nozzle at two places corresponding to two states of the yarn, so that the yarn interior can be dyed in one way and the yarn exterior can be dyed in a different way; to this end, a single nozzle comprises a number of hot air supply ducts which are identical to the duct 5 and which are disposed at various places of the nozzle. Of course, the evaporation facility just described can be adapted to any nozzle, whatever the direction and number of the hot air supply ducts may be.

In the variant shown in FIG. 6, the fluid supply duct 5 has associated with it a secondary duct 25 closed by an ultrasonic generator in the form of a loudspeaker 26 comprising a metal diaphragm or any other diaphragm or member adapted to produce hyper-frequency vibrations. On no-load operations, the pressure upstream of a venturi 27 is just below the critical pressure. In the bulb 3 the hot fluid changes over to subsonic flow. Corresponding to each vibration transmitted by the diaphragm 26 is a pressure wave which produces a local pressure increase in the venturi throat, the fluid changing over to supersonic flow in the nozzle. The changeover from one form of flow to another produces a shock wave which texturizes the yarn.

Of course, the ultrasonic generator just described is of use with any of the nozzles hereinbefore described and can be used together with the evaporation facility shown in FIG. 5. A number of ultrasonic generators of the same frequency can be associated with the said number of hot air supply ducts distributed uniformly around the nozzle axis. Each generator produces a shock wave field which is staggered in time by an amount corresponding to the inverse of the number of generators. The generators can produce a rotating shock wave field whose frequency is the same as the frequency of the generators.

In the case shown in FIG. 7, two generators 28,29 are associated with one another and are disposed in two hot air supply ducts 30,31 disposed symmetrically of the axis of the nozzle 2. The resulting shock wave fields are therefore in phase opposition.

The use of ultrasonic generators enables the invention to be used to reproduce a standard yarn. To this end, and as shown in FIG. 8, a yarn 32 which it is required to copy is placed in the throat of a venturi 33 in a duct 34 through which air flows. A microphone 35 is placed at one end of the duct 34 and transmits the vibrations which it picks up to an amplifier 36 connected to an ultrasonic generator 37 disposed in a duct 38 which extends to a venturi 39 of a hot air supply duct 40 for a nozzle (not shown). A textured yarn can therefore be produced which accurately copies the features of the control or standard yarn 32 as analysed by the microphone 35.

The aim of other variants shown in FIGS. 9 to 16 is to speed up texturization and the twisting-untwisting effects of the yarns.

In the embodiment shown in FIGS. 9 to 12, the ap paratuscomprises, as previously, a nozzle 2 whose bulb 3 receives hot air through a duct 5 comprising a venturi 41. The air in the duct 5 is at a pressure above the critical pressure. As the air goes through the venturi 41, the flow becomes supersonic and takes the form of a vortex whose axis is the axis of the nozzle 2 and which rotates in the direction indicated by arrows 42 and whose supersonic portion is bounded by the boundary layer in contact with the nozzle walls and by the leakage fluid flows at the nozzle entry and exit. The nozzle exit orifices are of large enough diameter not to disturb the annular flow.

In FIG. 9, which is a section along the line lX-lX of the device shown in FIG. 10, there are three concentric flow zones 43-45. The outer zone 43 is formed by the boundary layer and is the boundary near the nozzle walls for the supersonic flow. The central zone 44 is the supersonic flow zone, and the innermost zone 45 is the zone of return subsonic flow. The relative position of the boundary between the zones 43 and 44 depends upon the Reynolds number of the flow in contact with the nozzle walls. The relative position of the boundary between the zones 43 and 44 depends on the air intake pressure at the nozzle entry and corresponds to the minimum radius of curvature at which the latter pressure balances centrifugal force.

Referring to FIG. 10, yarn 1 for treatment enters through the bottom orifice of the nozzle, goes therethrough and leaves the nozzle through its top orifice associated with the bulb 3.

In a first kind of operation, the yarn l is in the positions shown in FIGS. 9 and 10 and is disposed at the boundary between the flow zones 43 and 44. The yarn 1 experiences an overall rotation, in the direction of the flows, around the nozzle axis. The positioning of the yarn between the zones 43 and 44 is stable, for if the yarn enters the zone 43, its rotational speed around the nozzle axis decreases since the linear flow speed is subsonic and decreases with distance away from the axis the centrifugal force balanced by the yarn tension decreases, and the yarn tends to move back towards the nozzle axis. If the yarn enters the supersonic zone 44, it is surrounded by the pressure shock wave which forces it towards the boundary between the flows 43 and 44, in which zones there are shock waves limiting supersonic flow. Also, if the yarn enters the zone 44, its rotational speed around the nozzle axis increases, centrifugal force' increases, and so the yarn tends to return to the boundary between the zones 43 and 44. The yarn is therefore stabilized. Also, the yarn has its outer surface near the subsonic flow of the zone 43 and its inner surface near the supersonic flow of the zone 44. A torque is therefore produced which tends to twist the yarn in the direction indicated by the arrow 46 and opposing the overall rotation of the yarn around the nozzle axis.

The speed of yarn rotation around the nozzle axis is of the order of 20,000 rpm and the twist speed is higher than 1,000,000 rpm. Because of its rotation around the nozzle axis, the initially twisted yarn untwists and spreads out, and so the rate of yarn twisting increases.

In a second kind of operation, the yarn is in the positions shown in FIGS. 11 and 12 and located on the boundary between the flow zones 44 and 45. The yarn is of an overall rotation around the axis in the directions of the flows. The position between the zones 44 and 45 is an unstable one, for if the yarn enters the zone 45, its rotational speed around the nozzle axis decreases so that centrifugal force decreases and the yarn tends to enter the zone 45 even further. The overall rotational speed of the yarn increases and the same tends to enter the zone 44 further.

However, some stability can be obtained. The yarn enters the zone 44, it is surrounded by a pressure shock wave which tends to bring the yarn into contact with the shock waves bounding the supersonic flow zone 44, so that the yarn tends to take up a position at the boundary between the zones 45 and 44. Consequently, by adjustment of yarn tensioning, the yarn can be positioned as required either between the zones 43 and 44 or between the zones 44 and 45. Similarly, and by analogy with what happens in the embodiment shown in FIG. 9, the yarn experiences a twisting torque which in this case twists the yarn in the same direction-indicated by the arrow 47-as the direction of overall yarn rotation around the nozzle axis. However, since the difference between the flow velocities on either side of the yarn is less than in the previous case, the twist speed is also less.

In a third kind of operation, the tension is adjusted permanently so that the yarn can go very rapidly from the position in FIG. 9 to the position in FIG. 11, then back to the position shown in FIG. 9, and so on, so that a single yarn having zones of opposite twist can be produced very rapidly.

FIGS. 13 to 16 show variants of the facilities shown in FIGS. 9 to 12.

Referring to FIGS. 13 and 14, the nozzle 2 comprises two identical hot air supply ducts 48,49 disposed symmetrically of the nozzle axis 2 and at the level of the bulb 3. This feature helps to increase the fineness of texturing. In this case, an increased number of hot air supply ducts can be provided.

Referring to FIGS. 15 and 16, the nozzle 2 comprises two identical hot air supply ducts 50,51 which are disposed at two different levels of the nozzle and which are adapted to produce flows in opposite directions. A friction zone is therefore produced between two supersonic flows, the friction zone having two shock wave zones in which the associated planetary twist and the texturing by shock waves proceed more rapidly.

Of course, a dye or blueing evaporator similar to the one shown in FIG. 5 can be associated with the facili ties shown in FIGS. 9 and 10.

Also, in all the facilities hereinbefore described yarn deformation is fixed therrnoplastically by the yarn being heated by the fluid flowing through the nozzle. Of course, the yarn can, if required, be heated prior to entering a nozzle supplied with cold air, or the wire can be preheated and the nozzle supplied with hot air.

The process according to the invention makes it possible to produce a wide variety of textured yarns, with or without twist, at speeds, e.g. of the order of 1,500 meters/minute, never previously approached. The texturing is much more regular than conventional processes can provide, inter alia by a pneumatic and thermodynamic looping of the facilities. The yarns are textured without rough contact of moving mechanical parts, and so delicate materials can be textured.

Also, in the facilities shown in FIGS. 1 to 3 and 6 to 8, a yarn having a variable twist can be produced by modification of the angle which the yarn leaving the nozzle makes with the nozzle axis; the maximum angle at which the nozzle can be used corresponds to an untwisted textured product. In the special case in which a double nozzle is used, a yarn without twist is produced if the textured product goes through a double nozzle whose direction of rotation is the opposite of the first double nozzle supplied with cold air, during the coolin f et tured am.

In tlfe fa ilitie fihown iii FIGS. 9 to 16, on the other hand, two opposite twists can be fixed separately or alternatively on a single yarn.

The products provided by the process and the variants thereof hereinbefore described can be recognized in several ways. One such way is a reversal of the direction of twist over a reduced length of the processed yarn, due mainly to random contacts between the yarn and the nozzle wall. Another sign is the appearance of a false Z or S-twist on the discrete filaments, due to the filaments rubbing on a surface which is either real (e.g. the noule wall) or virtual (boundary layer between a supersonic flow and a subsonic flow).

Although the invention has been illustrated and described with reference to one preferred embodiment thereof, it is to be understood that it is in no way limited to the details of such a preferred embodiment but is capable of numerous modifications with the appended claims.

What is claimed is:

1. An apparatus for converting textile threads, including a nozzle having a chamber with bounding surfaces in the form of a surface of revolution, said chamber having a substantially toroidal terminal part and an entry tube of small diameter with a section slightly increasing from its outer thread-entering end to its inner, larger end which merges with the smaller end of the toroidal terminal part, means for passing a thread through said chamber in longitudinal direction, at least one gas supply duct extending into said toroidal terminal part, a source of gas under pressure connected to said supply duct, a venturi near the junction of said duct with a nozzle, the gas in said source being at least at the critical pressure at or above which the gas at the outlet of the venturi flows at supersonic speed, whereby the gas initially flows through the nozzle at supersonic speed after it is passed through the venturi, and then produces shock waves near the thread as a result of the changes in the flow of the gas abruptly from supersonic to subsonic speed in said nozzle near the thread, means for guiding the thread so that it is subjected to the shock waves thus produced in the flowing gas, and means for continuously moving the thread under treatment in the nozzle at a desired tension.

2. Apparatus as set forth in claim 1 characterized in that the axis of such gas supply duct cuts the nozzle axis.

3. Apparatus as set forth in claim 1 characterized in that such gas supply duct joins the toroidal part of the nozzle substantially tangentially.

4. Apparatus as set forth in claim 1 comprising means for adjusting the tension at which the thread is subjected as it passes through the nozzle.

5 Apparatus as set forth in claim 1, comprising an ultrasonic generator in the air supply duct for modulating the shock waves in the gas stream. 

1. An apparatus for converting textile threads, including a nozzle having a chamber with bounding surfaces in the form of a surface of revolution, said chamber having a substantially toroidal terminal part and an entry tube of small diameter with a section slightly increasing from its outer thread-entering end to its inner, larger end which merges with the smaller end of the toroidal terminal part, means for passing a thread through said chamber in longitudinal direction, at least one gas supply duct extending into said toroidal terminal part, a source of gas under pressure connected to said supply duct, a venturi near the junction of said duct with a nozzle, the gas in said source being at least at the critical pressure at or above which the gas at the outlet of the venturi flows at supersonic speed, whereby the gas initially flows through the nozzle at supersonic speed after it is passed through the venturi, and then produces shock waves near the thread as a result of the changes in the flow of the gas abruptly from supersonic to subsonic speed in said nozzle near the thread, means for guiding the thread so that it is subjected to the shock waves thus produced in the flowing gas, and means for continuously moving the thread under treatment in the nozzle at a desired tension.
 2. Apparatus as set forth in claim 1 characterized in that the axis of such gas supply duct cuts the nozzle axis.
 3. Apparatus as set forth in claim 1 characterized in that such gas supply duct joins the toroidal part of the nozzle substantially tangentially.
 4. Apparatus as set forth in claim 1 comprising means for adjusting the tension at which the thread is subjected as it passes through the nozzle.
 5. Apparatus as set forth in claim 1, comprising an ultrasonic generator in the air supply duct for modulating the shock waves in the gas stream. 